Within a 13½ x 11½in (34 x 29cm) frame of semi-precious hardstones and ebony is an oval amethyst panel painted with a depiction of The Adoration of the Magi using the contours and lustre of the stone as a background.
Remarkably for such a high-status object, it was an over-the-counter consignment from a longstanding client who believed it had been in the family for at least two generations but held it in scant regard.
There was some minor damage to the pietra dura frame but it was in wholly original condition.
Seven telephone lines (two from America, five from Italy) plus five bidders in the room provided the competition on February 25. The buyer was an Italian dealer who is to send it to Southern Italy for further research in the hope of pinning down the artist or workshop.
The buyer's premium was 20 per cent.